Material forming apparatus



Dec. 23, 1952 N. E. EARLE MATERIAL FORMING APPARATUS 2 SHEETS-SHEET 1 Filed June 5, 1951 INVENTOR M EARLE ATTURNEV Dec. 23, 1952 N. EARLE 2,622,653

MATERIAL FORMING APPARATUS Filed June 5, 1951 2 SHEETS-SHEET 2 A TTOPA/EY Patented Dec. 23, 1 952 MATERIAL FORMING APPARATUS Norman E. Earle, Groveland, Mass., assignor to Western Electric Company, Incorporated, New York, N. Y., a corporation of New York Application J une 5, 1951, Serial No. 229,964

7 Claims.

This invention relates to material forming apparatus and particularly to safety control means for preventing injury to an operator using such apparatus.

Many types of devices have been developed to safeguard operators of such apparatus or machines, and each new type of machine requires the modification of old safety devices or the development of new ones. The observance of proper safety precautions is often regarded by machine operators as involving unnecessary effort or as reducing their work output. They therefore are apt to disregard safety instructions and to disable safety mechanisms wherever possible thereby greatly increasing the probability of accident. It is very common, for example, in an attempt to protect both the hands of the operator, to provide two widely spaced pushbutton switches, both of which must be held closed to initiate the operating cycle of the machine. The purpose of this type of safety device can be defeated, however, merely by fastening one of the switches in closed position, thereby leaving one of the operators hands free and hence subject to possible injury.

The object of this invention is a safety control in a material working machine which permits operation-of the machine only when the controls are manipulated in the prescribed, safe manner.

Broadly, the invention comprises a control system in which safe operation is assured by requiring the operator not only to use both hands to condition the machine for operation, but also by requiring him to operate the controls in the proper safe sequence and to hold the controls operated until the work cycle has been performed. In one embodiment of the invention a material forming apparatus has relatively operable material holding and forming elements under the control of spaced handles mounted for movement between their neutral and operating positions. The handles are normally urged into their neutral positions to prevent accidental operation thereof and have separate operating means under their control requiring movement of the handles into their operating positions in a given sequence to assure operation of the holding and forming elements. The holding element is in the form of a mandrel about which a strip of metal is to be bent. The forming unit is under the control of an electrical circuit and when actuated forms the metal strip about the mandrel. The springs for the handles are extended to provide the necessary force to hold their handles in their normal or neutral positions and at the same time to hold a member which supports a bar of conductive material in electrical engagement with contacts in the control circuit whereby breakage or removal of either spring will open the circuit at the contacts. One of the important safety features includes a latch for securing the mandrel in its operating or forming position, providing the handles are operated in a given sequence and for preventing operation of the forming unit, if this sequence of operation is not followed. Each handl causes operation of a switch, these switches being disposed in series in the control circuit to complete the circuit for operation of the forming unit.

Other objects and advantages will be apparent from the following detailed description when considered in conjunction with the accompanying drawings wherein:

Fig. 1 is a schematic illustration of portions of the apparatus and the control circuit therefor, the forming unit having been omitted to more clearly illustrate the other features of the apparatus;

Fig. 2 is a top plan view of the apparatus illustrating mainly the forming unit in its neutral position;

Fig. 3 is a top plan view of a portion of the apparatus illustrating the forming unit in its operated position; and

Fig. 4 is a fragmentary isometric view of a portion of the forming unit.

Referring now to the drawings, attention is first directed to Fig. 1 which illustrates a support Ii) having a shelf II for a strip of material l2 to be formed. The width of the shelf H is equal to or less than the thickness of the material 12. A surface IQ of the holder is in a position to cooperate with the shelf I l and accurately position the material. A mandrel l6 pivotally supported at i! for movement from its neutral or solid line position to its operated or dotted line position is provided with an aperture I8 to receive a latch l9.

Handles 2| and 22 are mounted at spaced positions on their shafts 23 and 24. Levers 25 and 26 are mounted on their shafts 23 and 24 and connected to the adjacent ends of springs 21 and 28. The other ends of the springs are connected near the ends of a support 30, formed preferably of a dielectric material. Stationary stops 29 are positioned to be engaged, for example, by projections of the levers 25 and 26 to locate the handles in their neutral positions. A bracket 3| mounted at a fixed position has notches 32 in leg portions 33 thereof to receive the support 30 in such a manner that it will be held in place by the forces inherent in the springs 21 and 28. A bar 35 of conductive material is mounted on the support 30 and positioned to electrically engage contacts 36 and 31 when the support is held in place. The contacts 36 are supported by a member 38 formed preferably of dielectric material and fixedly mounted on the bracket 3 A lever 40 mounted on the shaft 23 of the handle 2| is connected to a lever 4| by a rod '42. The lever 4| is operatively connected to the mandrel l6 through a shaft 43, a lever 44, a pullrod 45, and an arm 46 which is fixed to the mandrel. While the handle 2| is in its neutral position, the mandrel [6 will be in its neutral position,.but upon actuation of the handle to its operating position, the mandrel will be forced into its dotted line position adjacent the material |2.

The shaft 24 under the control of the handle 22 is operatively connected to the latch l9 through a lever 38 on the shaft 24, a rod 49, a lever 50, a shaft and a lever 52. The lever 52 has an elongate aperture 53 therein to receive the lower end of the latch and to bring about vertical movement of the latch during rocking motion of the lever. An arm 55 of the latch |9 is positioned with respect to a normally open switch 56 so that it will close the switch after the latch I9 enters the aperture IQ of the mandrel. A switch 58 is positioned with respect to the lever 25, or any other suitable arm mounted on the shaft 23, to be moved into closed position as the handle 23 reaches its operating position. The switches 56 and 58 are connected in series in the control circuit 60 requiring the closing of both switches to complete the circuit. The circuit 6D is supplied with power from an outlet such as 61 in a 110 volt circuit.

The forming unit shown in Figs. 2 to 4 inclusive includes a substantially U-shaped member 65 supported by a ram 66 of a piston (not shown) in an air cylinder S7. The air cylinder is supplied with air under pressure from a supply line 68 through a valve 69 operated by a solenoid to direct air through a line ll when the solenoid is energized and to direct air through a line 12 when the solenoid is deenergized. The conventional exhausting means for the opposite ends of the air cylinder are employed but not shown.

The leading ends of the legs of the U-shaped member 65 are provided with rollers connected to the legs of the members by links it and provided with outwardly projecting pins H at both ends thereof to engage cams E8 to direct the path of movement of the rollers. Through this mechanism movement of the forming unit from its neutral position, shown in Fig. 2, to its operated position, shown in Fig. 3, will first form the material I?! into a U-shape. The rollers 15 under the control of their cams ill will bend the ends f the material inwardly toward each other to complete the rectangular formation of the material.

Considering now the operation of the apparatus, let it be assumed that the apparatus is in its neutral position, shown in Figs. land 2. The operator may, at this time, place the strip of material |2 on the shelf H of the holder l0. It is impossible for the operatorshand to be injured in any way during the feeding of the material to the apparatus, for even if the handle 22 should be operated accidentally, the forming unit will not be operated as it requires closing of both switches 56 and 51 to accomplish this result. It is therefore necessary that the handles 2| and 22 be operated in a given sequence.

After the material is located on its holder, the handle 2| is moved into its operating position. If the operator should foolishly leave his hand in the path of the mandrel, his hand would not be injured as only the force applied to the lever 2| by his other hand is applied to the mandrel to move it into its forming position. The forming unit is the only part of the apparatus that would injure the opera-tor. However, during its operation, both hands of the operator will be occupied by the required operations of the handles 2| and 22. Movement of the handle 2! into its operating position will close the switch 58 and as long as the mandrel is held in its forming position,

the switch 58 will remain closed. At this time the operator moves the handle 22 and during movement of this handle, the mandrel I6 is latched in place before the switch 56 is closed guarding against incorrect operation of the apparatus. Furthermore, the operator must continue to hold both handles in their operating positions for if he should release either or both handles, the control circuit would be opened, deenergizing the solenoid T0 to return the forming unit to its neutral position. It is not possible for the operator to operate the apparatus without using both hands to do so. Failure or removal of either one of the springs 21 or 28 would result in the immediate dropping or pulling away of the support 30 to open the control circuit. A foolproof operating mechanism for a material forming machine is therefore embodied in the apparatus.

It is to be understood that the above described arrangements are simply illustrative of the application of the principles of the invention. Numerous other arrangements maybe readily devised by those skilled in the art which will embody the principles of the invention and fall within the spirit and scope thereof.

What is claimed is:

1. In a material forming apparatus having relatively operable material holding and forming elements, spaced handles mounted for movement between their natural and operating positions, a member to form an electrical connection in a control circuit mounted to require holding forces at spaced portions thereof to maintain the connection, whereby the removal of either force will cause the member to move and break the connection, springs connecting their respective handles and portions of the members providing the said forces for the member and normally urging the handles into their neutral positions, operable means under the control of one of the handles to move the holding element into its operating position, and operable means under the control of the other handle and the control circuit to operate the material forming element.

2. Ina material forming apparatus having relatively operable material holding and forming elements, spaced handles mounted for movement between their neutral and operating positions, a member to form an electrical connection in a control circuit mounted to require holding forces at spaced portions thereof to maintain the connection, whereby the removal of either force will cause the member to move and break the connection, springs connecting their respective handles and portions of the members providing the said forces for the member and normally urging the handles into their neutral positions, operable means under the control of one of the handles to move the holding element into its operating position, operable means under the control of the other handle and the control circuit to operate the material forming element, and a latch actuable by the last named means to secure the holding element in its operating position.

3. In a material forming apparatus having relatively operable material holding and forming elements, spaced handles mounted for movement between their neutral and operating positions, a member to form an electrical connection in a control circuit mounted to require holding forces at spaced portions thereof to maintain the connection, whereby the removal of either force will cause the member to move and break the connection, springs connecting their respective handles and portions of the members providing the said forces for the member and normally urging the handles into their neutral positions, operable means under the control of one of the handles to move the holding element into its operating position, operable means under the control of the other handle and the control circuit to operate the material forming element, and normally open switches in series in the control circuit closed by the movement of the handles into their operating positions.

4. In a material forming apparatus having relatively operable material holding and forming elements, spaced handles mounted for movement between their neutral and operating positions, a member to form an electrical connection in a control circuit mounted to require holding forces at spaced portions thereof to maintain the connection, whereby the removal of either force will cause the member to move and break the connection, springs connecting their respective handles and portions of the members providing the said forces for the member and normally urging the handles into their neutral positions, operable means under the control of one of the handles to move the holding element into its operating position, operable means under the control of the other handle and the control circuit to operate the material forming element, a latch actuable by the last named means to secure the holding element in its operating position, and normally open switches in series in the control circuit closed by the movement of the movement of the handles into their operating positions in a given sequence, the latch interrupting movement of the handle for the holding element into its operating position to close its switch upon movement of the other handle into its operating position out of the said sequence.

5. A material forming apparatus comprising a support for material to be formed, a mandrel normally positioned away from the support and mounted for movement into its forming position in engagement with the material, a unit operable to form the material about the mandrel, first and second handles mounted at spaced positions for movement between their neutral and operating positions, means operable by movement of the first handle into its operating position to move the mandrel into its formin position, and means operable by the holding of the first handle in its operating position and movement of the second handle into its operating position to operate the unit.

6. A material forming apparatus comprising a support for material to be formed, a mandrel normally positioned away from the support and mounted for movement into its forming position in engagement with the material, a unit operable to form the material about the mandrel, first and second handles mounted at spaced positions for movement between their neutral and operating positions, means operable by movement of the first handle into its operating position to move the mandrel into its forming position, an electrical control circuit for the unit, a normally open switch in the circuit closed by the first handle, and a normally open switch in series with the other switch in the circuit closed by movement of the second handle into its operating position to operate the unit.

7. A material forming apparatus comprising a support for material to be formed, a mandrel normally positioned away from the support and mounted for movement into its forming position in engagement with the material, a unit operable to form the material about the mandrel, an electrical control circuit for the unit, first and second handles mounted at spaced positions for movement between their neutral and operating positions, springs normally urging the handles in their neutral positions, a member normally held in position by the spring for the handles to close an electrical connection in the control circuit and free to move upon the breakage or removal of either or both springs to open the circuit, means operable by movement of the first handle into its operating position to move the mandrel into its forming position, and means operable by holdin the first handle operated and operating the second handle to close the circuit to operate the unit.

NORMAN E. EARLE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,382,102 Lukaszewski June 21, 1921 1,701,822 Nordquist Feb. 12, 1929 2,177,131 Bihler Oct. 24, 1939 

